The present invention relates to telescoping slide assemblies having interconnected stationary, intermediate, and chassis slide members that slide relative to each other between a fully extended position and a fully retracted position. In particular, the invention relates to a latch mechanism for locking the intermediate slide member to the stationary slide member to prevent inadvertent retraction of the intermediate slide member. More particularly, the invention relates to latch mechanisms that are releasable by movement of the chassis slide member relative to the intermediate slide member to provide uninterrupted retraction of the slide assembly between the fully extended position and the fully retracted position.
A conventional telescoping slide assembly typically includes a stationary slide member, a chassis slide member, and an intermediate slide member. The intermediate slide member is positioned and configured to move the chassis slide member toward and away from the stationary slide member so that an object (e.g. drawer, equipment rack, platform, etc.) supported by the chassis slide member can be moved into and out of a cabinet or other housing.
Typically, a pair of telescoping slide assemblies are positioned in side-by-side spaced-apart parallel relation so that either a chassis platform or one or more pieces of equipment can be carried on the two side-by-side chassis slide members. It is also common to use a pair of telescoping slide assemblies to support a cabinet drawer between a retracted position inside the cabinet and an extended position outside the cabinet.
The stationary slide member is typically mounted to a fixed frame to anchor the slide assembly. The frame could be a cabinet, a truck bed, or any other suitable platform. For example, it is known to use telescoping slide assemblies to slide heavy pieces of equipment into and out of a truck bed.
Various kinds of equipment or loads can be anchored to the movable chassis slide members so that such loads can be moved easily relative to the truck bed or the like during telescoping extension and retraction of the intermediate and chassis slide members in each slide assembly relative to the stationary slide members that are anchored to the truck bed. Typically, a telescoping slide assembly is extended and retracted manually by an operator and thus must be capable of moving heavy loads easily and quickly under the control of an operator during loading of equipment onto the truck and unloading of equipment from the truck.
It is known to provide locking interconnections between each of the three slide members so that extension or retraction of the slide members relative to each other can be prevented. Since these locking interconnections must generally be manually engaged and disengaged, separate manual unlocking actions are required before such a drawer or equipment can be retracted. The use of a locking mechanism to prevent relative movement of two sliding tracks until manual release of the locking mechanism is known. See, for example, U.S. Pat. No. 4,200,342 to Fall et al.
Telescoping slide assemblies are able to retract to move the equipment or load from the extended position to a retracted position. Again, the operator initiates the retraction process by actuating a release mechanism to allow the chassis slide member to retract relative to the intermediate slide member. Typically, when the chassis slide member reaches its fully retracted position, the operator must actuate the release mechanism a second time to release the intermediate slide member for retraction relative to the stationary slide member. In many instances, the need for a second actuation of the release mechanism is a nuisance. Thus, telescoping slide assemblies that provide mechanisms for allowing the slide members to fully retract without stopping at a partly retracted position would be an improvement over conventional slide assemblies.
Releasable lock-out latch mechanisms for allowing a slide assembly to retract to a fully retracted position without stopping at a partly retracted position are known. See, for example, U.S. Pat. Nos. 4,549,773 and 4,560,212, both to Papp et al. The Papp et al. '773 and '212 patents disclose a releasable lock out latch coupled to the intermediate slide member and positioned to extend from the inner end (in direction of retraction) of the intermediate slide member. A portion of the latch is biased by a spring so as to extend into the path of the chassis slide member. Unfortunately, by extending from the inner end of the intermediate slide member, the lock-out latch increases the length of the slide mechanism. Moreover, the latch is susceptible to movement against the force of the biasing spring due to vibrations or jostling of the slide assembly to release the slide members inadvertently for retraction relative to each other.
An improved releasable lock-out latch mechanism would not add to the overall length of the slide assembly. The improved latch would also positively couple the slide members together in an extended position, thereby avoiding inadvertent release of the slide mechanism.
According to the present invention, a latch mechanism is provided for use with a telescoping slide assembly having interconnected stationary, intermediate, and chassis slide members that are movable between a fully retracted position and a fully extended position. The latch mechanism includes blade means for locking the intermediate slide member in the fully extended position relative to the stationary slide member. Lip means is formed on the stationary slide member to provide a catch for the blade means. The blade means is pivotally coupled to the intermediate slide member and positioned on the intermediate slide member for movement through an aperture formed in the intermediate slide member during pivoting movement of the blade means relative to the intermediate slide member. The blade means includes notch means for engaging the lip means formed on the stationary slide member to prevent movement of the intermediate slide member relative to the stationary slide member in a first direction. Biasing spring means is coupled to the intermediate slide member for normally urging the blade means in a downward direction to engage the lip means.
The chassis slide member includes camming means for lifting the notch means out of engagement with the lip means to allow the intermediate slide member to retract relative to the stationary slide member. Ramp means formed on the blade means engages the camming means to lift the notch means out of engagement with the lip means in response to retraction of the chassis slide member relative to the intermediate slide member.
In preferred embodiments of the invention, the ramp means includes a ramping edge formed on the blade means and configured to face a downward and extending direction opposite to the first direction. As the camming means moves in a retracting direction, the camming surface engages the ramping edge and the blade means is lifted upwardly, disengaging the notch means from the lip means.
Additional objects, features, and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of a preferred embodiment exemplifying the best mode of carrying out the invention as presently perceived.